Avalanche Forecast

Issued: Mar 10th, 2013 10:17AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Monday

Weather Forecast

Monday: Overcast conditions with moderate to heavy snowfall developing late in the day / Moderate southwest winds / Freezing level at 1200mTuesday: Moderate to heavy snowfall / Moderate to strong southwest winds / Freezing level at 1300mWednesday: Heavy snowfall / Moderate southwest winds / Freezing level at 1700mNote: The bulk of the precipitation is expected to fall in the south of the region for the forecast period

Avalanche Summary

Before the weekend a size 2.5 slab avalanche was observed above the Squamish River Valley on an east aspect at 2300m. The size of this slide suggests it may have failed on the February 20th interface. On Saturday loose wet avalanches to size 1.5 were reported, one of which triggered a size 2 storm slab in south facing alpine terrain. These occurred in response to solar warming. A few size 1 windslabs have also been reported. These formed from strong southwest winds on Saturday.

Snowpack Summary

Dribs and drabs of recent snowfall have been shifted by strong southwest winds into touchy new windslabs in exposed areas. In more sheltered terrain, surface hoar and/or surface facets are likely to exist. A sun crust has formed on south facing terrain.Between 60 and 110cm below the surface is a layer surface hoar which was buried on February 20th. Although this layer has a history of producing large avalanches, triggering this layer has now become difficult, and would most likely require a very large trigger on a steep, unsupported slope.Below this interface, the snowpack is strong and well settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs exist and are reportedly reactive in some areas. New wind/ storm slabs are also expected to form with forecast weather on Monday afternoon.
Be alert to conditions that change throughout the day.>Be cautious as you transition into wind affected terrain.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 11th, 2013 2:00PM